Rotary pump with integral rotor construction

ABSTRACT

A rotary pump of unitary rotor construction disposed within a housing having a cylindrical inner surface. A tubular shaft extends from one end of the rotor and supplies fluid to the axis of the rotor. A pair of axially spaced cylindrical disks concentric with the shaft form with the inner wall of the housing a pump discharge chamber. A pair of cylindrical pumping cams eccentrically formed on the shaft are disposed outwardly of said cylindrical disks with the eccentricity or high point of one cam being diametrically opposite the high point of the other. A pair of radially movable gate members urged into engagement with diametrically opposed surfaces of each of said cams define with the outer surface of the cam, the housing and concentric disks four separate fluid chambers, one on each side of said gates. The gates engaged with one cam lie in a plane approximately perpendicular to a plane containing the gates engaged with the other cam. A suction port extends radially from the bore of the tubular shaft to the outer surface of each cam and a pressure or discharge port extends axially from the outer surface of each cam into communication with the annular discharge chamber disposed intermediate said cams. The suction and pressure ports of each cam are located on opposite sides of its high point and located diametrically opposite the suction and discharge ports respectively of the other cam.

United States Patent Belcher 1 5] Mar. 14, 1972 [54] ROTARY PUMP WITH INTEGRAL ROTOR CONSTRUCTION Charles E. Belcher, 811 Silver Street, Agawann, Mass. 01001 [22] Filed: Oct. 14,1970

[21] Appl.N0.: 80,591

[72] Inventor:

[52] U.S.Cl ..4l8/186,418/l88,418/215,

Primary ExaminerCarlton R. Croyle Assistant Examiner-R. E. Gluck Att0meyChapin, Neal & Dempsey [5 7] ABSTRACT A rotary pump of unitary rotor construction disposed within a housing having a cylindrical inner surface. A tubular shaft extends from one end of the rotor and supplies fluid to the axis of the rotor. A pair of axially spaced cylindrical disks concentric with the shaft form with the inner wall of the housing a pump discharge chamber. A pair of cylindrical pumping cams eccentrically formed on the shaft are disposed outwardly of said cylindrical disks with the eccentricity or high point of one cam being diametrically opposite the high point of the other. A pair of radially movable gate members urged into engagement with diametrically opposed surfaces of each of said cams define with the outer surface of the cam, the housing and concentric disks four separate fluid chambers, one on each side of said gates. The gates engaged with one cam lie in a plane approximately perpendicular to a plane containing the gates engaged with the other cam. A suction port extends radially from the bore of the tubular shaft to the outer surface of each cam and a pressure or discharge port extends axially from the outer surface of each cam into communication with the annular discharge chamber disposed intermediate said cams. The suction and pressure ports of each cam are located on opposite sides of its high point and located diametrically opposite the suction and discharge ports respectively of the other cam.

5 Claims, 6 Drawing Figures f 708 W m i 5 J 5 j r. a N\ 1 1 3 B m 3 Patented March 14, 1972 Patented March 14, 19 72 3,649,141

INVENTOR.

C/mr/es 15: e/cfier ROTARY PUMP WITH INTEGRAL ROTOR CONSTRUCTION BACKGROUND The principal object of this invention is to provide a rotary pump of simple and economical construction with a minimum of moving parts, which is capable of achieving uniform and high volume output.

Another object of this invention is to provide a rotary pump having a rotor of unitary construction capable of being driven clockwise or counterclockwise.

A further object of this invention is to provide for a rotary pump a rotor constructed to minimize axial thrust and to minimize wear on the pump bearings.

The above and other objects of this invention will be more readily apparent from the accompanying description and with reference to the accompanying drawings, in which:

FIG. 1 is a cross sectional view showing a pump embodying this invention;

FIG. 2 is an elevational view showing the rotor portion of the pump;

FIG. 3 is a sectional view along line 33 of FIG. 1;

FIG. 4 is a sectional view along line 4-4 of FIG. 1;

FIG. 5 is a view similar to FIG. 4 but with the rotor turned to a different operative position; and

FIG. 6 is a partial view showing an alternative form of gate construction.

Referring in detail to the drawings, in the illustrated embodiment the pump embodying this invention comprises a housing 8 having an inner cylindrical surface 10. The opposite ends of the housing are closed by a pair of end caps 12 and 14 secured to the housing by any suitable means, such as circumferentially spaced bolts 16. O-rings 17 are provided between the housing of the pump and the end plates to provide a fluid seal and an outlet or discharge tube 19 extends from the housing at approximately the midpoint of its length. Each of the end caps includes a roller bearing 18 which supports at one end of the pump the drive shaft 20 and at the other end a bore or tubular fluid supply conduit 22. A small bleed off passage 23 is provided to relieve fluid pressure from the end seal 17 to the suction or low pressure side of the pump rotor. A tubular supply conduit 26 communicates in end-to-end relation with the conduit 22. As shown, the conduit 26 is connected to the pump by means of a number of bolts 28 circumferentially spaced about a flange 30 which extends radially outward of the inner end ofthe conduit. While in the embodiment shown, the rotor is integral, it is within the scope of this invention to provide a spline connection between the drive shaft 22 and the tubular conduit of the rotor so that the drive end can be connected to either end of the rotor for use in pumps rotatable in a direction opposite the direction shown.

A unitary rotor, shown generally at 32, FIGS. 1 and 2, comprises at approximately the center thereof a pair of axially spaced cylindrical disks 34 and 34 concentric with the axis a of the rotor as shown in FIG. 2. An annular recess 36 is disposed between the opposed surfaces of the disks 34 and 34', and together with the inner wall and the housing forms a discharge chamber 36 for the pump with which a discharge passage or fitting 19 communicates. The diameter of the cylindrical disks 34 and 34 is made of such clearance relative to the inner wall of the pump housing that the high pressure discharge liquid is capable of forming a thin film between the outer surface of the disks and the housing so that a thin liquid film supports the rotation of the rotor and thus minimizes wear on the bearings 18.

Extending axially from the outer surface of each of the concentric disks 34 and 34' is a pumping cam 38 and 38', respectively. Each of the pumping cams 38 and 38' is of cylindrical configuration of smaller diameter than the disks 34 and 34' and arranged eccentrically relative to the axis a of the rotor shaft. The radius of the cams is less than the radius of the disks by the eccentricity such that the outermost surface portions or high points of the pumping cams and the cylindrical disks 34 and 34 are generally flush over a small arc of about 5-l0 of their circumference. The eccentricity or high points of the two cams extends in diametrically opposite directions, as shown in FIG. 2. The diameters of the two pumping cams 38 and 38 as indicated are smaller than the disks 34 and 34' so that when the rotor is disposed within the cylindrical housing 8. a chamber covering an arc of approximately 350 is formed about the periphery of each of the cams from its high point. The bore 22 extends coaxially within the rotor from its inlet end at the conduit 26 to a point within the pumping cam 38' so as to supply fluid to both pumping cams in the manner to be described below. The axial length of the cams and dimensional relationship of cam size to disk size are selected to achieve a desired pump displacement.

Each cam has a suction port 40 and 40', respectively, extending radially from the tubular conduit 22 through the outer surface of the cams. The suction ports are located at an acute angle following, in its direction of rotation, the high point of the cam. Suction ports 40 and 40 are located on diametrically opposite positions of the rotor (FIG. 1). Each cam is also provided with a pressure or discharge port 42 and 42' extending axially inwardly so as to provide a fluid passage to the annular discharge chamber 36 from the rims of the respective pumping cams 38 and 38. The discharge ports are located at an acute angle in advance, in its direction of rotation, of the high point of each cam. The pressure ports 42 and 42' are also located on diametrically opposite sides of the rotor. In the embodiment shown, each port comprises two adjacent, radially extending orifices interconnected by a chordal passage to provide the desired quantity offluid flow.

A pair of gates 44 and 46 are engaged with diametrically opposite surface portions of cam 38, and gates 44 and 46' are similarly disposed to engage cam 38. The gates 44 and 46 engaged with one cam, lie in a plane generally perpendicular to the plane containing the outer gates 44' and 46 and are hydraulically retained in surface-to-surface contact with the outer surface of the cams as by means of a small passageway or conduit 47 which extends from the discharge connection 19 into chambers 54 above the gates 44and 46 and 44' and 46 The fluid urges the gates into surface-tosurface contact with the rims of the pumping cams. In addition, springs 49 urge the gates inwardly against the cams rims while the pump is being started and before it has developed full pressure. Once the pump is in full operation the force exerted by the fluid itself is sufficient to maintain the gates in operating. contact with the pumping cams.

An alternate form of gate instead of the unitary block construction heretofore described is shown in FIG. 6 and comprises a pair of laterally spaced plate or blade members 5] urged inward by leaf spring 53. The blade members are independently movable and operable hydraulically in the same manner as the gates 44 and 46 but with much less area of contact with the rotor pumping cam.

As best seen in FIG. 3, in which the gates 44 and46' are shown engaged with the high and low points of the cam 38, the gates divide the peripheral chamber about the two pumping cams into two separate chambers 48 and 50' for cam 38' and chamber 48 and 50 for cam 38 (FIGS. 4 and 5), each covering an arc of about allowing approximately 10 for the surface engagement of the cams high point and pump wall. As the cam rotates in the direction shown, from its FIG. 3 position, the volume of chamber 50' diminishes to force the fluid contained therein through the discharge port 42 and into the annular chamber 36. At the same time chamber 48' increases in volume at the same rate as the chamber 50 decreases to create a suction which draws fluid into the chamber through the suction port 40'. Suction continues to fill the camber until the suction port has rotated past the gate 46. When this happens, as shown for cam 38 in FIG. 4, the two chambers 48 and 50 reverse functions; chamber 50 becoming the suction chamber and 48 the discharge chamber.

In the position illustrated by FIG. 4, the chamber 48 has just been filled with the fluid being pumped. Continued rotation of the cam 38 from this position will bring the discharge ports 42 into the chamber 48, as shown in FIG. 5. At the same time, chamber 50 starts filling with fluid in a suction cycle. Thus, for one revolution of each pumping cam, two suction and two discharge cycles take place. Both pumping cams operate in es sentially the same manner except that one is 180 out of phase with the other. The reason for this is that the discharge and suction ports are located on diametrically opposite positions on the rotor as is the high point of the cam. in addition, as mentioned previously, the line along which gate members 44' and 46 operate is approximately perpendicular to the line along which gates 44 and 46 operate. Thus, in one rotation of the rotor there is an overlap of approximately 90 in the suction and discharge cycles. That is, one cam starts its suction and discharge cycles 90 in advance of the corresponding cycles of the other cam. This insures smooth, nonsurging output from the pump.

When fluid is forced into the ports 42 and 42' leaving from the two pumping cams, it is forced into the annular chamber 36 in opposite directions, thus resulting in substantial balance of axial thrust on the rotor. The fluid is discharged from annular chamber 36 through the discharge coupling 19.

Having thus disclosed my invention, what is claimed is:

l. A rotary pump comprising a housing with a rotor rotatably supported therein, said rotor having a shaft of tubular construction serving as a fluid supply conduit for said pump, said rotor including axially spaced pumping cams eccentrically disposed about said shaft with an annular discharge chamber therebetween, each of said cams including a suction port extending from said conduit to the rim of said cam and a discharge port extending from said rim to said discharge chamber, and a pair of radially movable gate members urged into engagement with the diametrically opposed surfaces of each of said cams.

2. A rotary pump as set forth in claim 1 in which the eccentricity of each of said cams extends in diametrically opposite directions, and in which the discharge and suction ports of one cam are disposed diametrically opposite the discharge and suction ports respectively of the other cam.

3. A rotor pump as set forth in claim 2 in which said rotor is of integral construction 4. A rotary pump as set forth in claim 3 in which said rotor includes a pair of axially spaced cylindrical disks concentric with said shaft and defining with the inner wall of the pump housing said annular discharge chamber, said pumping cams being of cylindrical configuration extending in height axially from the outer surface of said disks and of a radius less than the radius of said disks by the extent of eccentricity of said cams, said pumping cams being concentrically disposed on said shaft so that the rim of each cam, at it high point, is generally flush with the rim of the adjacent disk over a small arc of the circumference of said disk, said discharge ports being disposed forwardly of the high point of said cam, in its direction of rotation, and said suction ports trailing said high point, in its direction of rotation, said disks, gate members, pump housing and rims of said cams providing about each cam a pair of fluid chambers which alternately serve as pumping and suction chambers during rotation of said rotor within said housing.

5. A rotary pump comprising a housing with a generally cylindrical inner surface, a shaft supported rotor disposed within said housing, said rotor comprising axially spaced cylindrical disks concentric with said shaft and forming with the inner wall of the pump housing an annular discharge chamber, a pair of cylindrical pumping cams of smaller diameter than said disks eccentric with respect to said shaft such that the eccentricity of each extends in diametrically opposite directions, said shaft being tubular in part to provide a fluid passage therein, each cam including a suction port extending radially from said fluid passage to the rim of said cam and a discharge pprt extending from the rim of each of said cams into communication with said annular discharge chamber and a pair of radially movable gate members urged into engagement with diametrically opposed surfaces of each of said earns, the discharge ports being located forward of the high point of said cams in their direction of rotation and on diametrically opposite sides of the rotor, said suction ports trailing said high points and on diametrically opposite sides of the rotor, and a discharge opening in said housing communicating with said discharge chamber. 

1. A rotary pump comprising a housing with a rotor rotatably supported therein, said rotor having a shaft of tubular construction serving as a fluid supply conduit for said pump, said rotor including axially spaced pumping cams eccentricallY disposed about said shaft with an annular discharge chamber therebetween, each of said cams including a suction port extending from said conduit to the rim of said cam and a discharge port extending from said rim to said discharge chamber, and a pair of radially movable gate members urged into engagement with the diametrically opposed surfaces of each of said cams.
 2. A rotary pump as set forth in claim 1 in which the eccentricity of each of said cams extends in diametrically opposite directions, and in which the discharge and suction ports of one cam are disposed diametrically opposite the discharge and suction ports respectively of the other cam.
 3. A rotor pump as set forth in claim 2 in which said rotor is of integral construction
 4. A rotary pump as set forth in claim 3 in which said rotor includes a pair of axially spaced cylindrical disks concentric with said shaft and defining with the inner wall of the pump housing said annular discharge chamber, said pumping cams being of cylindrical configuration extending in height axially from the outer surface of said disks and of a radius less than the radius of said disks by the extent of eccentricity of said cams, said pumping cams being concentrically disposed on said shaft so that the rim of each cam, at it high point, is generally flush with the rim of the adjacent disk over a small arc of the circumference of said disk, said discharge ports being disposed forwardly of the high point of said cam, in its direction of rotation, and said suction ports trailing said high point, in its direction of rotation, said disks, gate members, pump housing and rims of said cams providing about each cam a pair of fluid chambers which alternately serve as pumping and suction chambers during rotation of said rotor within said housing.
 5. A rotary pump comprising a housing with a generally cylindrical inner surface, a shaft supported rotor disposed within said housing, said rotor comprising axially spaced cylindrical disks concentric with said shaft and forming with the inner wall of the pump housing an annular discharge chamber, a pair of cylindrical pumping cams of smaller diameter than said disks eccentric with respect to said shaft such that the eccentricity of each extends in diametrically opposite directions, said shaft being tubular in part to provide a fluid passage therein, each cam including a suction port extending radially from said fluid passage to the rim of said cam and a discharge port extending from the rim of each of said cams into communication with said annular discharge chamber and a pair of radially movable gate members urged into engagement with diametrically opposed surfaces of each of said cams, the discharge ports being located forward of the high point of said cams in their direction of rotation and on diametrically opposite sides of the rotor, said suction ports trailing said high points and on diametrically opposite sides of the rotor, and a discharge opening in said housing communicating with said discharge chamber. 